Within the field of neuromodulation, the use of electrical modulation for treating neurological disease, such as Parkinson disease, essential tremor, dystonia, chronic pain, and epilepsy has been widely discussed in the literature. Neuromodulation includes administrating either or both of stimulating or inhibiting signals to increase, decrease or block neural activity. It has been recognized that electrical modulation holds significant advantages over lesioning. For example, lesioning results in irreversible destruction of neural tissue. Electrical modulation, on the other hand, permits modulation of the target neural structures and does not require the destruction of neural tissue.
Disorders manifesting gross physical dysfunction, not otherwise determinable as having psychiatric and/or behavioral origins, comprise the vast majority of those pathologies treated by deep brain stimulation. However, there have been disclosures on improving abnormal psychiatric function in psychiatric patients, such as those suffering from Obsessive Compulsive Disorder, depression and other psychiatric disorders. For example, efforts have been made to treat certain psychiatric disorders with peripheral/cranial nerve stimulation as well as deep brain stimulation. An investigational protocol in 2000 demonstrated partial benefits with vagus nerve stimulation in patients with depression (Biological Psychiatry 47: 216-286, 2000).
Methods of improving cognitive function have also been described by stimulating the intralaminar nuclei (see U.S. Pat. No. 6,539,263 to Nicholas Schiff).
However, these references either described treating psychiatric function in patients suffering from psychiatric diseases or describe improving cognitive function by stimulating very specific areas of the brain. A need exists to treat neuropsychological functions in patients suffering not from psychiatric disorders, but neurocognitive disorders. Further a need exists for modulating a region that affects neuropsychological function.